KR20050078008A - Lenticular sheet and transmission type screen using the same - Google Patents

Abstract

In the lenticular sheet of the present invention, a lenticular lens array is formed on the incidence side of the transparent substrate, and a light-transmitting resin portion formed in the concave-convex shape consisting of a plurality of protrusions and concave portions is formed on the exit side. It is formed by printing a light absorbing layer on the concave portion, while using the existing printing process as it is, it is possible to improve the formability by providing the tolerance required for fine pitch shape processing, and at the same time improve the contrast characteristics.

Description

Lenticular sheet and transmission type screen using the same

The present invention relates to a lenticular sheet, a method of manufacturing the same, and a transmissive screen using the lenticular sheet. More specifically, the present invention relates to a lenticular sheet that can be used for a micro display (MD) using a conventional printing process, and The manufacturing method and the transmissive screen using such a lenticular sheet are related.

As a light source used in a projection TV, projectors such as a small CRT (Cathode Ray Tube), LCD (Liquid Crystal Display), and DLP (Digital Light Processing) are used. It is called a micro display (MD) type light source. In addition, the transmissive screen used here is composed of a fresnel sheet and a lenticular sheet. The lenticular sheet has a cylindrical lens array called a lenticular lens at the entrance and / or exit surface. Located at the exit surface, it has a light absorbing layer to limit the reflection of external light. In order to form such a light absorption layer, the light absorption layer was printed and used in the lenticular sheet of the screen for CRT. However, in the MD screen, since the width of the lenticular lens is as small as several hundreds to several tens of micrometers, the light absorption layer must be precisely formed, and thus, the conventional printing process cannot be used in the MD lenticular sheet. In addition, it is important to provide a sufficient degree of contrast on the screen because the projection TV using the MD type light source is not sufficient in the contrast characteristics of the light source itself, and is a primary means for providing sufficient contrast characteristics on the screen. It is important to ensure a sufficient area of the light absorbing layer relative to the total area of the screen.

In order to manufacture a lenticular sheet for MD, the method proposed in US Pat. No. 58,702,24 or JP-A-59-121033 is applied after applying a photoresist having adhesive properties to the exit side of the substrate of the lenticular sheet and then paralleling it. When the light is irradiated to the incident lens side of the lenticular sheet, the adhesive property of the portion where the light is collected by the light focused on the photoresist surface through the incident lens is removed, and after the toner is applied, the toner is removed. The toner adhered only to the portion not condensed to form a light absorbing layer. 6 shows a lenticular sheet 10 produced in this manner. This method is a fine pitch (lenticular) lenticular lens 13 in that the alignment of the lenticular lens 13, the incident lens and the light absorbing layer 18 is automatically made in the manufacturing process of the lenticular sheet 10. The lenticular sheet 10 having a) has an advantage that it is easy to manufacture.

However, such a manufacturing method requires an additional process such as application of photoresist, uniform irradiation of light, coating and removal process of toner, and has a disadvantage in that time and cost are increased as compared with a conventional lenticular sheet manufacturing process.

Furthermore, since the lenticular sheet does not secure a light absorbing layer having a sufficient area when light condensed into the photoresist layer 16 during the manufacturing process has aberrations or is diffused by the diffusion layer to increase the area of the focal point, As shown in FIG. 6, the light absorbing layer 18 has a structure having a diffusion layer 12 (in the viewer-side direction). This structure has the disadvantage of increasing the amount of light reflected toward the viewer's eyes since diffusion reflection by the diffusion layer 18 is performed before the external light is absorbed by the light absorption layer 18, thereby inhibiting the contrast characteristics of the entire screen. There was this.

An object of the present invention is to solve the above problems, to provide a lenticular sheet and a method of manufacturing the moldability improved by providing a tolerance required for fine pitch shape processing while using the existing printing process as it is.

Another object of the present invention is to provide a lenticular sheet having improved contrast characteristics and a method of manufacturing the same.

It is a further object of the present invention to provide a transmissive screen which provides the tolerances required for fine pitch shape processing to improve moldability and at the same time improve contrast characteristics.

In order to achieve these and other objects, the lenticular sheet according to the present invention has a lenticular lens array formed on one side of a transparent substrate, and a light transmitting resin portion formed in a concave-convex shape formed of a plurality of protrusions and recesses on the other side. The light absorption layer is formed in each concave portion of the light transmissive resin portion. At this time, each projecting portion of the light transmissive resin portion is located at a portion where the focal point of each lenticular lens of the lens array portion is in focus.

A transmissive screen according to another feature of the invention consists of a Fresnel lens and a lenticular sheet above.

Method for producing a lenticular sheet according to another feature of the present invention

Forming cylindrical lenticular lenses on one side of the transparent substrate;

Forming a concave-convex shape consisting of a plurality of protrusions and concave portions using a light transmitting resin on the other side of the transparent substrate, wherein each of the protrusions is formed so as to be located at a portion where the focus point of each lenticular lens is formed; And

The step of printing a light absorbing layer in the concave-convex shape.

Hereinafter, a lenticular sheet according to the present invention, a method for manufacturing the same, and a transmissive screen will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

First, a lenticular sheet according to an embodiment of the present invention will be described with reference to FIG. 1. The lenticular sheet 200 includes a cylindrical lenticular lens array 230 on the transparent substrate 270 toward the incident surface. Each cylindrical lenticular lens 231 constituting the lenticular lens array 230 corresponds to a minimum pixel size that can be displayed by the projection TV, and for a micro display, a width P of several hundreds to several tens of micrometers. Have

On the exit surface side of the lenticular sheet 200, a transparent resin portion 210 having a concave-convex shape formed of a plurality of recesses 212 and protrusions 211 is formed on the substrate 270, and a transparent resin portion Each of the protrusions 211 of 210 may be positioned at a portion in which the lenticular lens 231 of the lens array 230 is in focus.

In addition, the cross-sectional shape of each of the protrusions 211 is formed to be narrowed to form a normal line and a cross-sectional inclination angle θ of the lenticular sheet surface, it is effective to prevent the scattering of the light collected by each lenticular lens 231.

The cross-sectional inclination angle θ of the protrusion 211 is the distance between the line connecting the two end points of the lenticular lens 231 and the focal point of the lenticular lens is F, the width of the lenticular lens is P, It is preferable to satisfy Formula (1).

The light absorbing layer 220 formed by the conventional printing method is formed on the concave portion 211 of the light transmissive resin part 210, and the light absorbing layer 220 is preferably formed to the height of the protrusion 212. The final surface of the protrusion 212 is the final exit surface 260.

In addition, when selecting the resin which has the light-diffusion characteristic, the light transmissive resin part 210 does not need to form a separate light-diffusion layer.

On the other hand, the value of the width d of the light absorbing layer 220 with respect to the width P of each lenticular lens 231 is

d / P ≥ 0.6

Is preferably,

d / P ≥ 0.8

More preferably. That is, the light absorption layer 220 should occupy at least 60% or more, more preferably 80% or more of the total area of the lenticular sheet 200 to improve the contrast.

The method for manufacturing the lenticular sheet 200 is formed by forming a cylindrical lenticular lens array 230 on one side of the transparent substrate 270, using a light-transmitting resin on the other side of the transparent substrate 270 The protrusion 211 and the concave portion 212 to form an uneven shape, each protrusion 211 is formed so as to be located in the portion where the focus of each lenticular lens, and then to the uneven protrusion 211 It is achieved by printing a light absorption layer by a conventional printing method.

Referring to FIG. 2, the transmissive screen 500 using the lenticular sheet 200 of FIG. 1 is described. The screen 500 includes a Fresnel lens 300 and a lenticular sheet 200.

The Fresnel lens 300 is a lens having a thin sheet shape while having all the optical characteristics of the original lens by dividing the thick lens into concentric bands, and emitting from the light source 400. The beam passes through the Fresnel lens 300 to function as a substantially parallel beam.

That is, the image projected from the light source 400 is formed by the Fresnel lens 300 and the lenticular lens array 230 of the lenticular sheet 200 at the protrusion 211 of the light transmissive resin portion 210.

3 is a detailed view for calculating the tolerance of the alignment on the optical axis. The width of the final surface of the protrusion 211 located at the exit of the lenticular sheet is the difference P-d between the width P of each lenticular lens 231 and the width d of the light absorbing layer 220. S is the concentration angle of the maximum luminous flux focused by one lenticular lens 231, F is the distance from the straight line connecting the two end points of the lenticular lens 231 to the focus point F, the width of the lenticular lens P, the light absorbing layer When the thickness of 220 is h and the distance from the straight line connecting the two end points of the lenticular lens 231 to the end of the light absorbing layer 220 is L, the final value of the light absorbing layer 220 when F> L The half width a of the luminous flux in the plane is

Where tan (s / 2) = P / 2F

to be. Therefore, the alignment tolerance T _op on the optical axis has the value of the following equation (2).

On the other hand, when the optical axis of the lenticular lens 231 is exactly aligned in the center of the protrusion 211, the tolerance T _t for the thickness of the lenticular sheet 200 is as follows.

Therefore, it is possible to know the range of the distance F (the distance from the straight line connecting the two end points of each lenticular lens 231 to the focal point) according to the thickness of the lens from the above equation. That is, when the thickness of the lenticular sheet 200 is thinner than the reference thickness, for example, the focus of the lenticular lens 231 is formed after the final exit surface 260 as shown in FIG. 4. That is, the distance from the two end points of the lenticular lens 231 to the interface between the light transmissive resin portion 210 and the light absorbing layer 220 is referred to as L, and between the light transmissive resin portion 210 and the light absorbing layer 220. When the distance from the boundary of to the focal point is l,

Since F≤L + l, F satisfies the following equation (4).

In addition, referring to the case where the thickness of the lenticular sheet 200 is thicker than the reference thickness, for example, the focus of the lenticular lens 231 is formed before the protrusion 211 as shown in FIG. 5. At this time, since F≥L + h-l, the following equation (4) is obtained.

Therefore, F must satisfy the following equation (6) from equations (4) and (4).

Accordingly, if the range of the distance F from the straight line connecting the two end points of each lenticular lens 231 to the focal point is within a certain range as shown in Equation 6, the performance of the lenticular sheet is not affected. Lenticular sheets can be manufactured with sufficient tolerances.

In addition, the distance F between the line connecting the two end points of each lenticular lens and the focal point of the lenticular lens is within the range of Equation 6

L-h / 2 ≤ F ≤ L + h / 2

It is preferable to satisfy.

An example of such a lenticular sheet is as follows. The width P of each lenticular lens is 255 μm, the value of the distance F from the straight line to the focal point connecting the two end points of the lenticular lens is 269.4 μm, the thickness h of the light absorbing layer is 20 μm, and the width d of the light absorbing layer is 216.8. The lenticular sheet of which the refractive index of the micrometer, the lenticular lens, and the resin of the light transmissive resin portion was 1.53, and the refractive index of the transparent base material 270 was 1.67. At this time, the tolerance on the optical axis according to the overall thickness of the lenticular sheet is shown in Table 1 below.

Thickness (mm) L (mm) Optical axis tolerance (±) (mm) 0.320 0.229 0.000 0.325 0.234 0.003 0.330 0.239 0.005 0.335 0.244 0.007 0.340 0.249 0.010 0.345 0.254 0.012 0.350 0.259 0.014 0.355 0.264 0.017 0.360 0.269 0.019 0.365 0.274 0.017 0.370 0.279 0.014 0.375 0.284 0.012 0.380 0.289 0.010 0.385 0.294 0.007 0.390 0.299 0.005 0.395 0.304 0.003 0.400 0.309 0.000

In the present example, as can be seen in Table 1, when forming a lenticular sheet with a lenticular sheet thickness of 0.360 mm, the allowable tolerance on the optical axis is the largest, so that the moldability can be greatly improved at such thickness. .

The lenticular sheet of the present invention and the transmissive screen using the same provide a tolerance necessary for processing a fine pitch shape to a degree that can be used for a projection TV for a micro display, and the like.

In addition, the lenticular sheet manufacturing method of the present invention can be manufactured using the existing printing process as it is, there is an effect that the process is simple and saves time and cost compared to the conventional manufacturing method of the lenticular sheet for micro display. .

1 is a view showing a lenticular sheet according to an embodiment of the present invention,

2 is a view showing a transmissive screen according to the present invention,

3 is a detailed view for calculating the tolerance on the optical axis,

4 and 5 are detailed views showing the case where the thickness of the lenticular sheet is thinner and thicker than the reference thickness, respectively.

6 is a diagram illustrating a conventional lenticular sheet.

Claims (12)

Transparent substrates; A lens array unit formed of cylindrical lenticular lenses and formed on one side of the substrate; A light transmissive resin portion formed in an uneven shape formed of a plurality of protrusions and recesses on the other side of the substrate; And A light absorbing layer printed on the concave portion of the light transmitting resin portion Including; Each projection of the light transmissive resin portion is a lenticular sheet, characterized in that located in the portion where the focus of each of the lenticular lens of the lens array portion. The method of claim 1, The light transmitting resin portion has a light diffusing property, characterized in that the lenticular sheet. The method of claim 1, Each projection has a narrow cross-sectional shape that forms a predetermined cross-sectional inclination angle with the normal of the lenticular sheet. The method of claim 3, When the inclination angle θ of the protruding portion is a distance between the line connecting the two end points of each lenticular lens and the focal point of the lenticular lens is F, the width of the lenticular lens is P, The lenticular sheet characterized by the above-mentioned. The method of claim 1, The width of the lenticular lens of the lens array unit is P, the distance from the straight line connecting the two end points of the lenticular lens to the protrusion of the light transmitting resin portion is L, the thickness of the light absorbing layer is h, and the light When the width of the protrusion of the transmissive resin portion is d, the distance F between the line connecting the two end points of each lenticular lens and the focal point of the lenticular lens is Lenticular sheet characterized by satisfying the. The method of claim 5, The distance between the line connecting the two end points of each lenticular lens and the focal point of the lenticular lens is F L-h / 2 ≤ F ≤ L + h / 2 Lenticular sheet characterized by satisfying the. The method of claim 1, The width P of each lenticular lens of the lens array unit and the width d of the light absorbing layer d / P ≥ 0.6 The lenticular sheet characterized by the above-mentioned. The method of claim 7, wherein The width P of each lenticular lens of the lens array unit and the width d of the light absorbing layer d / P ≥ 0.8 The lenticular sheet characterized by the above-mentioned. Forming cylindrical lenticular lenses on one side of the transparent substrate; Forming a concave-convex shape consisting of a plurality of protrusions and concave portions using a light transmitting resin on the other side of the substrate, wherein each of the protrusions is formed at a portion where the focal point of each lenticular lens of the lens array unit is in focus; And Printing a light absorption layer on the protrusions of the uneven shape; Method for producing a lenticular sheet comprising a. The method of claim 9, The method of manufacturing a lenticular sheet, wherein the light transmitting resin has light diffusing characteristics. A transmissive screen comprising a Fresnel lens and a lenticular sheet, The lenticular sheet Transparent substrates; A lens array unit formed of cylindrical lenticular lenses and formed on one side of the substrate; A light transmissive resin portion formed in an uneven shape formed of a plurality of protrusions and recesses on the other side of the substrate; And A light absorbing layer printed on the concave portion of the light transmitting resin portion Including; Each projection of the light transmissive resin portion is a transmissive screen, characterized in that located in the portion where the focal point of each lenticular lens of the lens array portion. The method of claim 11, And said light transmitting resin portion has light diffusing characteristics.